Post on 29-May-2015
description
transcript
A Peek at 5G
F a n g X i eC h i n a M o b i l e R e s e a r c h I n s t i t u t e
Outline
• Challenges and Requirements
• TDD: An efficient transmission mode for 5G
• C-RAN: Centralized/Cooperative/Cloud/Clean RAN
• Beyond Cellular Generation
• LTE-Hi: Small cell enhancement for Hotspot/indoor
• Summary
1. Traffic grows explosively but not the revenue
Mobile data traffic will increase 1000 times in 10 years
Profit per bit will continuously decrease in the future years
2. Traffic distribution appears as unbalanced
Imbalance between the terminal type: in 2010, smart phone’s global penetration rate is 13%, while it
contribute 78% traffic load from the terminal
Geographic imbalance: in 2009, more than 50% mobile service happened at home/office; while this
percentage is 63% in China. Most of the data service happens in low mobility indoor and dense urban
Home access Internet
Office access Internet
On-road access Internet
USA 37.8% 19.6% 42.6%UK 45.6% 17.8% 36.6%Germany 43.4% 15.3% 41.3%France 33.1% 21.7% 45.2%Italy 39.6% 21.4% 39.0%South Africa 48.6% 21.4% 30.0%
Mexico 28.2% 27.6% 44.2%Brazil 36.7% 24.7% 38.6%Korea 33.7% 31.7% 34.6%India 45.9% 30.4% 23.7%China 30.1% 32.7% 37.2%
3. Spectrum has been fragmented and used up
Surging power consumption
The majority of power consumption from RAN
4. Power consumption plays an important role in OPEX
High CAPEX/OPEX of RAN result from BS equipment room
Summary of Challenges and Requirements for future
Explosive growth of mobile data traffic
Spectrum Fragmentation
Unbalanced DL and UL traffic
low‐band spectrum used up
Higher date rateHigher Spectrum Efficiency
Efficient utilization of un‐paired spectrum
Flexible adaptation of DL/ UL traffic
More usable spectrum
Huge power consumption Better energy saving
Challenges Requirements
Outline
• Challenges and Requirements
• TDD: An efficient transmission mode for 5G
• C-RAN: Centralized/Cooperative/Cloud/Clean RAN
• Beyond Cellular Generation
• LTE-Hi: Small cell enhancement for Hotspot/indoor
• Summary
Promising Features of TDD
• Channel Reciprocity
– Advanced MIMO/Beamforming
• Flexible allocation of DL/UL resource
– Traffic adaptation
– Energy saving
• Unpaired frequency usage
– Flexible deployment
– Suitable for higher band and large bandwidth
TDD based downlink CoMP: Joint Transmission
1,92,54
2,47
5,46
2,81
6,15
3,01
6,58
0
2
4
6
8
2Tx�(X)/2Rx 8Tx(XXXX)/2Rx
Cell average spectrum efficiency
0,0560,098
0,047
0,183
0,078
0,227
0,101
0,266
0,00
0,10
0,20
0,30
2Tx�(X)/2Rx 8Tx(XXXX)/2Rx
Cell Edge spectrum efficiency 25%
SU-BF MU-BF Intra-Site�CoMP 3�site/9�cells�CoMP
SU-BF MU-BF Intra-Site�CoMP 3�site/9�cells�CoMP
TDD based 3D-MIMO
• High frequency lead to feasible antenna array size
• Active antenna array technology makes it feasible to achieve cost effective implementation
• TDD promises more accurate CSI by UL sounding to exploit the potential gains of CSIT
Feasibility of TDD 3D-MIMO
• System capacity improvement• Small intra-cell interference• High beamforming gain• High spatial multiplexing gain
• Energy efficiency improvement
What can be achieved?
Example: 8*8 = 64
• Background– Current Systems are Interference-
Limited– Interference Suppression by MIMO is
limited to 2-Dimension– New AAS design facilitating the
exploitation of elevation dimension
Promising Features of TDD
• Channel Reciprocity
– Advanced MIMO/beamforming
• Flexible allocation of DL/UL resource
– Traffic adaptation
– Energy saving
• Unpaired frequency usage
– Flexible deployment
– Suitable for higher band and large bandwidth
Dynamic TDD achieves better spectrum & energy efficiency
Fast DL/UL switching
Higher throughput by fast adaptation to
instantaneous traffic
Fast switching off of DL transmission to
save energy
• Semi-static TDD:DL/UL resource allocation based on TDM in the same carrier
Asymmetric DL/UL resource allocation adapts to asymmetric DL/UL traffic
Promising Features of TDD
• Channel Reciprocity
– Advanced MIMO/Beamforming
• Flexible allocation of DL/UL resource
– Traffic adaptation
– Energy saving
• Unpaired frequency usage
– Flexible deployment
– Suitable for higher band and large bandwidth
TDD becomes dominate for wide band allocation
• Fragmented spectrum• Difficult to find wideband paired spectrum (low
to medium frequency)• Future system is expected to be wideband
Current situations
• Use un-paired spectrum• Easy to allocate wideband, e.g. 100MHz• Better utilization of spectrum
TDD: A better choice
Outline
• Challenges and Requirements
• TDD: An efficient transmission mode for 5G
• C-RAN: Centralized/Cooperative/Cloud/Clean RAN
• Beyond Cellular Generation
• LTE-Hi: Small cell enhancement for Hotspot/indoor
• Summary
…
RRU
RRU
RRU
RRU
RRU
RRU
RRU
Virtual BS Pool
Distributed RRU
High bandwidth optical transport
network
Real-time Cloud for centralized
processing
…Centralized Control and/or Processing• Centralized processing resource
pool that can support 10~1000 cells
Collaborative Radio• Multi-cell Joint scheduling and
processingReal-Time Cloud • Target to Open IT platform• Consolidate the processing
resource into a Cloud• Flexible multi-standard operation
and migrationClean System Target• Less power consuming• Lower OPEX• Fast system roll-out
C-RAN Concept
Soft base-station – seamlessly scalable and upgradable
C-RAN Benefits
Lower CAPEX and OPEXSave up to 15% CAPEX and 50% OPEX compared to distributed BTS 3G network*
0 100 200 300
Faster system roll outDue to simpler remote radio site, system roll out can save up to 1/3 the time*
Lower energy consumptionSave up to 71% of power compared to traditional RAN system*
*Source: Base on China Mobile research on commercial networks
• Traditional Cellular Network is coverage-based and is not energy efficient, especially when traffic is low
• Data traffic growth densifies BS• Beyond cellular generation
– On-off small cells (AP)– Signaling and data decoupling– Uplink and downlink decoupling
Enhanced Macro BS
Densed BS
Ericsson soft-cell GreenTouch BCG2
Hetnet
Beyond Cellular Generation
19
BCG structure
signaling
data
downlink
uplink
downlink Zzzz…
Zzzz…
LTE-Hi Motivations
Currently, 60% Voice Traffic & 70% Data Traffic Happen Indoor
In Future, 90% Indoor/Hotspot Traffic Estimated
To Accommodate Explosive Growth Of Data Traffic In Such Cases, The Followings Means Need To Be Considered:
– Denser Network (But Difficult For Macro Layers)– Easy-to-deploy Low Power Node– Larger Bandwidth– New Techniques To Improve The Spectrum Efficiency & Throughput
These Motivates The So-called LTE-Hi (Hotspot & Indoor) To Ensure The Competitiveness Of 3GPP In Local Area
Characteristics
• High Data Rate Needed• Low Mobility• Rich Scattering• Low Multi-Path Latency• Discontinuous Coverage• High Degree Of Isolation
Between Cells
EnhancementEnhancement
• Physical Layer:• New transmission technology, e.g.
NCT, dynamic TDD, 256QAM
• Denser Network:• Hetnet, Multi-Type/Easy-to-deploy
Nodes for Indoor/Hotspot
• Larger Bandwidth:• Expand to higher spectrum for
larger bandwidth.
Characteristics & Possible Enhancements
Summary
• Challenges and Requirements for 5G
• Promising features of TDD makes it a most efficient transmission mode for Beyond 4G system– Channel Reciprocity makes it a sufficient way to utilize advanced
MIMO/Beamforming– Dynamical TDD adapts to asymmetrical traffic and lead to higher
capacity and energy efficiency – Unpaired frequency usage utilizes the limited spectrum in most
efficient way and lead to flexible deployment
• C-RAN: Centralized/Cooperative/Cloud/Clean RAN
• Beyond Cellular Generation
• LTE-Hi: Small cell enhancement for Hotspot/indoor
If you can imagine it You can achieve it
Thank you